From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C990CC43331 for ; Tue, 24 Mar 2020 13:12:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F379208D5 for ; Tue, 24 Mar 2020 13:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055574; bh=4tIolwig/eG6kdesbtHxMMmhATOgOH0aKutX8PYYDHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1WfNULHPPGQysSQTp26HIw+gYzXeH29lv/GDrZPrvRYIFjK9XFjVWlhOA4wsRpxdX nAPFrkGLZq/MXvSz0yXq1ulg4Y/+vgZIQQTknSbtLxg4ZU1V6aVRWxtM2tEEw6wPEa TKPCqKnCVczra3ObLr9Tcs7ld3E5QXtZvtx6928g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727737AbgCXNMw (ORCPT ); Tue, 24 Mar 2020 09:12:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:58750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727719AbgCXNMs (ORCPT ); Tue, 24 Mar 2020 09:12:48 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C9F6820775; Tue, 24 Mar 2020 13:12:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055568; bh=4tIolwig/eG6kdesbtHxMMmhATOgOH0aKutX8PYYDHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DAOrmlXhVzafrWzFRk8GbNO4N3tOh2pnB02Vk0bSDwLkCWjMAa90NSGLU6kLVy4Zn s0HFHoRCfaid+hDObI6mR2YM5y8AFWLGnx10fwUEN/316ldMGdIj3ChvkTb5nIF+vQ kX53kFQai+5IqVaZeW+nVkbstiSEkfUfgN2v3hQc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 4.19 26/65] ALSA: line6: Fix endless MIDI read loop Date: Tue, 24 Mar 2020 14:10:47 +0100 Message-Id: <20200324130800.538866245@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324130756.679112147@linuxfoundation.org> References: <20200324130756.679112147@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai commit d683469b3c93d7e2afd39e6e1970f24700eb7a68 upstream. The MIDI input event parser of the LINE6 driver may enter into an endless loop when the unexpected data sequence is given, as it tries to continue the secondary bytes without termination. Also, when the input data is too short, the parser returns a negative error, while the caller doesn't handle it properly. This would lead to the unexpected behavior as well. This patch addresses those issues by checking the return value correctly and handling the one-byte event in the parser properly. The bug was reported by syzkaller. Reported-by: syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/000000000000033087059f8f8fa3@google.com Link: https://lore.kernel.org/r/20200309095922.30269-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/line6/driver.c | 2 +- sound/usb/line6/midibuf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -320,7 +320,7 @@ static void line6_data_received(struct u line6_midibuf_read(mb, line6->buffer_message, LINE6_MIDI_MESSAGE_MAXLEN); - if (done == 0) + if (done <= 0) break; line6->message_length = done; --- a/sound/usb/line6/midibuf.c +++ b/sound/usb/line6/midibuf.c @@ -163,7 +163,7 @@ int line6_midibuf_read(struct midi_buffe int midi_length_prev = midibuf_message_length(this->command_prev); - if (midi_length_prev > 0) { + if (midi_length_prev > 1) { midi_length = midi_length_prev - 1; repeat = 1; } else